Another nod to the Prizm. One of my requirements was to be as single lense as possible simply acknowledging permanent drawer space for second lenses, and especially to not get caught up in Anon's game of selling different lenses based on frame color. The M2 is going to be a three lense goggle for a lot of people, and that's three bills on the budget. But at least they have earth magnets
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Anyway, I have fairly sensitive eyes to bright light (always in sunglasses) and I use the Flight Deck rose prizm in all light conditions. It is definitely an excellent low light and broad spectrum contrast lense, and I haven't felt a need to "darken" more. To the extent that's a personal thing, I think providing excellent terrain contrast over a decent spectrum is more important than "low" or "high" light. We don't ski light, we ski terrain contrast (or lack thereof) and I'm not sure that correlates most directly to either optical quality or extra lenses.